爲了實現長輪詢,我嘗試了不同的解決方案,並沒有獲得任何好的結果。在使用deferredResult提交響應後無法轉發
所以我決定看看異步方法和DeferredResult
。 在這裏我實施了REST
消費者。
@Controller("sessionStateRest")
@RequestMapping("ui")
public class SessionStateRest extends BaseRestResource {
private final Queue<DeferredResult<ModelAndView>> mavQueue = new ConcurrentLinkedQueue<>();
/**
* Rest to check session state.
*
* @return string with session state
*/
@RequestMapping(value = "/session")
public @ResponseBody DeferredResult<ModelAndView> sessionState() {
final DeferredResult<ModelAndView> stateResult = new DeferredResult<>();
this.mavQueue.add(stateResult);
return stateResult;
}
@Scheduled(fixedDelay = 5000)
public void processQueue() {
for(DeferredResult<ModelAndView> result: mavQueue) {
if (null == SecurityHelper.getUserLogin()) {
result.setResult(createSuccessResponse("Invalidated session"));
mavQueue.remove(result);
}
}
}
}
通過知道它應該處理的請求隊列中,如果每5秒和setResult
條件爲真。
同步版本會是這樣的
@RequestMapping(value = "/sync")
public ModelAndView checkState() {
if (null == SecurityHelper.getUserLogin()) {
createSuccessResponse("Invalidated session");
}
return null; // return something instead
}
但過一段時間後,我得到了一個異常
java.lang.IllegalStateException: Cannot forward after response has been committed
at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:349) ~[tomcat-embed-core-7.0.
39.jar:7.0.39]
at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:339) ~[tomcat-embed-core-7.0.39
.jar:7.0.39]
at org.apache.catalina.core.StandardHostValve.custom(StandardHostValve.java:467) [tomcat-embed-core-7.0.39.jar:7.0.3
9]
at org.apache.catalina.core.StandardHostValve.status(StandardHostValve.java:338) [tomcat-embed-core-7.0.39.jar:7.0.3
9]
at org.apache.catalina.core.StandardHostValve.throwable(StandardHostValve.java:428) [tomcat-embed-core-7.0.39.jar:7.
0.39]
at org.apache.catalina.core.AsyncContextImpl.setErrorState(AsyncContextImpl.java:417) [tomcat-embed-core-7.0.39.jar:
7.0.39]
at org.apache.catalina.connector.CoyoteAdapter.asyncDispatch(CoyoteAdapter.java:294) [tomcat-embed-core-7.0.39.jar:7
.0.39]
at org.apache.coyote.http11.AbstractHttp11Processor.asyncDispatch(AbstractHttp11Processor.java:1567) [tomcat-embed-c
ore-7.0.39.jar:7.0.39]
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:583) [tomcat-embed-cor
e-7.0.39.jar:7.0.39]
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312) [tomcat-embed-core-7.0.39.jar:7.
0.39]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) [na:1.7.0_67]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) [na:1.7.0_67]
at java.lang.Thread.run(Thread.java:745) [na:1.7.0_67]
什麼問題?我應該設置DeferredResult
的超時時間嗎?
你應該首先讓它工作**沒有** DeferredResult',然後嘗試添加它。我不明白這段代碼可以做什麼......我不確定春天可以理解哪一個更糟糕;-) –
@SergeBallesta我無法爲異步調用找到解決方案 – lapots
我的意思是*首先讓它同步工作* –